Before using this section, perform the ’’On-Board Diagnostic (OBD) System Check’’ and verify all of the following items:
• The ECM and CHECK ENGINE Lamp (MIL) are operating correctly.
• There are no DTCs stored.
• Tech 2 data is within normal operating range. • Verify the customer complaint and locate the
correct symptom in the table of contents. Perform the procedure included in the symptom diagnosis chart.
• Ask the customer if the specified engine oil and fuel are used.
Visual/Physical Check
Several of the symptom procedures call for a careful visual/physical check. This can lead to correcting a problem without further checks and can save valuable time.
This check should include the following items:
• Check if commercial accessory power is taken from the ECM power.
• ECM grounds for cleanliness, tightness and proper location.
• Vacuum hoses for splits, kinks, and proper connectors, as shown on the ’’Vehicle Emission Control Information’’ label. Check thoroughly for any type of leak or restriction.
• Air intake ducts for collapsed or damaged areas. • Wiring for proper connections, pinches and cuts. • Check if fuel leakage, pipe damage or dent is
found in the fuel system.
Intermittents IMPORTANT:
An intermittent problem may or may not turn on the CHECK ENGINE Lamp (MIL) or store a DTC. Do not use the Diagnostic Trouble Code (DTC) charts for intermittent problems. The fault must be present to locate the problems.
Most intermittent problems are caused by faulty electrical connections or wiring. Perform a careful visual/physical check for the following conditions:
• Poor mating of the connector halves of a pin not fully seated in the connector (backed out). • Improperly formed or damaged pin.
• All connector pin in the problem circuit should be carefully checked for proper contact tension.
• Poor pin-to-wire connection. This requires removing the pin from the connector body to check.
Road test the vehicle with a Digital Multimeter (5- 8840-0366-0) connected to a suspected circuit. In case of a malfunction, abnormal voltage indicates the presence of a fault in the circuit being checked. Use a scan tool to help detect intermittent conditions. The scan tools have several features that can be used to locate an intermittent condition. Use the following feature for find intermittent faults:
The check for loss of DTC memory, disconnect the intake air pressure sensor and idle the engine until the CHECK ENGINE Lamp (MIL) comes on. DTC32 should be stored and kept in memory when the starter switch is turned “OFF”. If not, the ECM is faulty. When this test is completed, make sure that you clear the DTC32 from memory.
A CHECK ENGINE Lamp (MIL) with no stored DTC may be caused by the following:
• CHECK ENGINE Lamp (MIL) wire to ECM shorted to ground.
• Poor ECM grounds.
Check for improper installation of electrical options such as lights, cellular phones, etc.
If DTC is not confirmed, snap-shot the Tech 2 data list, so that approximate faulty location can be estimated according to the follow-up performance or validity of numeric values, or identification of fixed values.
1. If a systematic error is recognized in numeric values, fundamental accuracy of instruments such as sensors will be faulty (for example, variations in sensor resistance value).
2. If a random error is recognized in numeric values, in general it will be caused by electrical (applied voltage) or mechanical troubles or noise.
3. If numeric values are fixed to high or low (fixed value error), the open wiring or short will occur in the circuits of instruments such as sensors. Further, you may be able to detect a trouble by disconnecting the connectors of related sensors and checking variations in numeric values or indication of Tech 2.
The part concerned is normal if a variation is recognized when its connector is disconnected, or it is faulty if no variation is recognized.
Related Sensors:
Coolant temperature sensor, CKP sensor, NE sensor, TCV, SPV, Fuel temperature sensor, EDU, Glow plug, Glow relay
Step Action Value(s) Yes No
1
DEFINITION:
Engine cranks, but does not start for a long time. Finally it starts, or may start but immediately stalls.
Was the ’’On-board Diagnostic (OBD) System Check’’ performed? — Go to Step 2 Go to "OBD System Check" 2
1. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found, correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?
—
Verify repair Go to Step 3
3 Was a visual/physical check performed? —
Go to Step 4
Go to Visual/ Physical Check
4
Check engine coolant temperature (ECT) sensor for shift in value.
1. After 1~7 hours with the hood up and the engine not running, connect the Tech 2. 2. Starter switch ’’ON’’, engine ’’OFF’’.
3. Compare engine coolant temperature to
intake air temperature (IAT).
Are ECT and IAT within the specified value of each other?
±5°C
Go to Step 8 Go to Step 5
5
1. Using Tech 2 , display the engine coolant temperature and note the value.
2. Observe the resistance of the engine
coolant temperature sensor.
Refer to ’’DTC 21 ECT Sensor Fault’’ for resistance specifications.
Is the resistance value ground resistance for the specified temperature?
—
Go to Step 7 Go to Step 6
6
Replace the ECT sensor. Is the action complete?
—
Verify repair —
7
Locate and repair high resistance or poor connection in the ECT signal circuit or the ECT sensor ground.
Is the action complete?
—
Verify repair —
8
1. Check if proper fuel is used. Also, check the fuel line for presence of air, the fuel filter for restriction, or the fuel warning lamp for lighting.
2. If a problem is detected, repair as
necessary.
Was a problem detected?
—
9
Check if the value of fuel temperature sensor varies.
1. Connect the Tech 2 without starting the
engine.
2. Starter switch "ON", engine "OFF"
3. Check if the resistance value of fuel
temperature sensor is proper for the specified temperature.
For the resistance specification, refer to "DTC 41F T Sensor Circuit High Voltage". 4. If a faulty, replace the fuel temperature
sensor.
Was the repair necessary?
—
Verify repair Go to Step 10
10
1. Observe the battery voltage.
2. If a problem is detected, repair as
necessary.
Was a problem detected?
—
Verify repair Go to Step 11
11
1. Check the operation of intake throttle. Perform visual check to find the following:
• Modification of throttle body (removal of the adjusting screw plug)
• Fault in air intake system — Check the air intake duct for dint, the air cleaner element for restriction, or the air intake system for presence of foreign materials.
• Check if the throttle body or air passage is blocked with foreign materials, or if foreign materials cling to the air passage, piston, throttle bore or throttle valve.
Was the repair necessary in either of above cases?
—
Verify repair Go to Step 12
12
1. Check the engine for evidence of the
following mechanical problems.
• Clogged nozzles, faulty valve opening pressure, or excessive nozzle tightening torque
• Weak compression pressure • Leak from cylinder head gasket • Wear or improper camshaft
2. If a problem is detected, repair as
necessary.
Was a problem detected?
—
Verify repair Go to Step 13
13
1. Review all diagnostic procedures within
this table.
2. If all procedures have been completed
and no malfunctions have been found, review/inspect the following:
• Visual/physical check. • Tech 2 data.
• All electrical connections within a suspected circuit and/or system.
3. If a problem is detected, repair as
necessary.
Was a problem detected?
—
Verify repair —